Brewed iced tea or non-carbonated drink dispenser

ABSTRACT

A beverage dispensing apparatus includes a mixing chamber for mixing hot water, a beverage concentrate and cold water, as well as one or more additives. The hot water and cold water are supplied at a predetermined flow rate at a predetermined proportion, regardless of the pressure of the water supply. A water heater supplies the hot water within a specified pressure range and without significant entrapped air.

REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. application Ser. No.10/402,944, filed Apr. 1, 2003 and claims priority thereto.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to beverage forming and dispensingsystems. More particularly, the present invention relates to beverageforming and dispensing systems for effectively preparing a beveragemixture from concentrate, and even more particularly to beverage formingand dispensing systems for effectively preparing a tea beverage mixturefrom concentrate.

2. Description of the Related Art

Beverages formed from concentrates are enjoyed around the world. Animportant advantage of forming a beverage from a concentrate is thatonly the concentrate need be shipped to the dispensing site; anyavailable water supply at the site can be used to form the bulk of thefinal mixed product. An advantage in forming traditionally breweddrinks, such as tea and iced tea, from concentrate is that thetime-consuming brewing process is eliminated.

There are many types of beverage making machines or appliances forforming beverages from concentrate. For example, U.S. Pat. No. 4,920,871relates to a beverage making appliance in which hot water is dischargedonto a brewing material, such as ground coffee or tea leaves, placed ina filter within a brewing funnel. In making iced tea, a brewedconcentrate discharges from the brewing funnel and combines with coldwater to form an iced tea stock. However, in this beverage-makingappliance, the concentrate must first be brewed and the ratio of thecold water and hot water concentrate is not precisely metered.

U.S. Pat. Nos. 4,309,939 and 4,579,048 relate to beverage brewingapparatuses in which beverage concentrate is first brewed from a drybeverage making material in a funnel. The concentrate is distributedinto a reservoir into which cold water is added to dilute theconcentrate to an acceptable strength. However, the cold water issupplied to the reservoir after the hot concentrate begins to flow intothe reservoir. Accordingly, the cold water and hot concentrate maystratify in the reservoir and not mix sufficiently.

U.S. Pat. No. 5,579,678 relates to an apparatus for automaticallysweetening tea in which heated water combines with tea in a brewingstation to form tea concentrate where it is mixed in a canister with adelivered sweetener. After sufficient tea concentrate is brewed anddelivery of the sweetener is completed, a quantity of diluting water ismixed with the hot tea concentrate and dissolved sweetener. Because thediluting water is supplied after a complete batch of tea concentrate isbrewed, the resulting mixture may stratify and not mix sufficiently. Itis known to agitate a mixture for prevention of stratification and formore effective mixing. However, more complicated structure and greaterpower consumption is necessary to effect agitation.

Additionally, conventional leaf tea urns are costly to clean andoperate, and are subject to undesirable and even dangerous growth ofbacteria inside the urn. The tea itself is a food source for bacteriaand the long residence times of tea product in the urn create anenvironment that promotes bacteria growth. Generally, bacteria coloniesstart to reproduce within several hours of making a fresh batch of tea.Typical post mix iced tea systems negate the disadvantages of the leaftea brewing process by directly mixing tea syrup with cold water.However, since there is no brewing step, the finished tea product doesnot have the same visual and taste quality as real, fresh-brewed icedtea.

From the foregoing, it is apparent that there is still a need for animproved method and apparatus for automatically preparing beverages fromconcentrate and ensuring that the resulting beverage mixture issufficiently mixed.

SUMMARY OF THE INVENTION

The present invention can provide a method and apparatus for preparing abeverage from concentrate.

The present invention can also provide a method and apparatus thateffectively mix a beverage concentrate and diluting water.

Further, the present invention can provide a method and apparatus thatprovide a residence time for the mixing of hot water and beverageconcentrate.

Still further, the present invention can provide a beverage mixingapparatus which is essentially a post-mix device but which has theappearance of a real brewing urn, such as a leaf tea brewer.

In addition, the present invention can provide a hot water heating unitthat can rapidly heat water and dispense it at a relatively low pressurewithout significant variation of flow rate during dispensing and withoutsignificant entrapment of air bubbles.

Moreover, the present invention can provide a beverage mixing apparatusthat can maintain a predetermined flow rate and a predeterminedproportion of hot and cold water regardless of pressure variations inthe water source.

Further, the present invention can provide a beverage mixing apparatusthat can reliably mix the various components of the resulting beverage.

These and other aspects, objects, and features of the present inventionwill become apparent from the following detailed description of thepreferred embodiments, read in conjunction with, and reference to, theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a beverage dispensing system according toan embodiment of the present invention;

FIG. 2A is a cross-sectional view of the water heater according to theembodiment;

FIG. 2B is a partial enlargement of FIG. 2A;

FIG. 3 is an exploded perspective view of the hot water tank;

FIG. 4 is an exploded perspective view of the mix chamber of theembodiment;

FIG. 5A is a cross-sectional view of FIG. 4 taken along section line5A-5A;

FIG. 5B is a cross-sectional view of FIG. 4 taken along section line5B-5B; and

FIG. 6 is a perspective view of the beverage dispensing apparatus of thepresent invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention relates to a beverage dispensing system that hasthe appearance of a system dispensing a beverage from a reservoir, butwhich is actually a post mix dispenser that instantaneously mixes anddispenses concentrate along with hot water and/or cold water.

In particular, the present invention relates to an iced tea dispenserthat looks and operates like a real leaf tea brewing urn, but which isactually a post mix dispenser that instantaneously mixes and dispensestea concentrate, hot water, and cold water. Additives, such as a liquidsweetener and an aroma-enhancing substance, may also be mixed anddispensed with the other elements. The finished tea product looks andtastes like fresh brewed leaf tea, but without the disadvantages of highmaintenance, high operational costs, and susceptibility to bacterialgrowth, which are inherent to leaf tea brewers. Additionally, theexterior of the dispenser appears to the user as a real leaf tea brewingurn.

The disclosure of U.S. patent Application Publication No. 2002-0074350,published Jun. 20, 2002, is incorporated herein by reference. Thispublication is based on U.S. patent application Ser. No. 09/965,829,filed Oct. 1, 2001, which is also incorporated herein by reference. Inaddition, the disclosure of U.S. patent application Ser. No. 10/100,164,filed Mar. 19, 2002, is incorporated hereinto by reference.

An embodiment of the present invention will now be described withreference to FIG. 1. Throughout the system, conventional beverage tubing(FDA approved for use with food products) is used to connect thecomponents of the system. Any of the beverage tubing lines may beinsulated to prevent heat loss or gain. In the beverage dispenser system110 shown in FIG. 1, a pressurized water source 124 supplies water tothe system 110 at typical domestic water pressures, i.e., approximately30-50 psi. As with the apparatus disclosed in the embodiments of theprior application, the dispensing apparatus can have the appearance of areal leaf tea brewing urn that dispenses beverage from a reservoir, butis actually a post-mix dispenser that can instantaneously mix anddispense tea concentrate along with hot and cold water. A sweetener andother additives, such as an aroma additive, can also be mixed therein.The correct proportion of hot and cold water can be maintainedregardless of the incoming water pressure.

Water from water source 124 is split into two separate flows of hotwater inlet line 128 and cold water inlet line 129 at water pressureregulator 126. Alternatively, a separate flow splitter can be positioneddownstream of the pressure regulator to separate the flows. The flowthrough hot water heater inlet line 128 is controlled by asolenoid-operated hot water heater inlet flow control valve 112, whichcontrols the flow of water into water heater 114, which will bedescribed in detail later. Flow of water out of heater 114 throughoutlet line 131 is controlled by solenoid-operated hot water outletvalve 130. Hot water outlet line 131 is connected to a mix chamber 122downstream of the valve 130. A solenoid-operated cold water supply valve156 is provided in cold water supply line 129. The outlet of line 129 isalso connected to the mix chamber 122.

Each of valves 112, 130 and 156 can be a conventional plunger valve,movable between fully-opened and fully-closed positions. In addition,each of valves 112 and 156 contains an orifice restriction of apredetermined size to meter the flow of water therethrough. That is,based on the relative sizes of the orifice restrictions of the twovalves, the correct proportion of hot and cold water can be maintainedregardless of the incoming water pressure at water source 124. Thisratio is preset by selecting an appropriate fixed orifice restrictionfor each valve. After the appropriate orifice restriction is set, thetotal water flow can be controlled by adjusting water pressure regulator126. For example, increasing the upstream pressure to the valvesincreases total flow, while decreasing pressure decreases flow.Alternatively, rather than incorporating the restrictions into thevalves, the restrictions can be separate components in the hot and coldwater lines. The hot water restriction 116 can be placed anywhere inline 128 between pressure regulator 126 and water heater 114 and thecold water restriction 158 can be placed anywhere in line 129 betweenregulator 126 and the mix chamber 122.

Referring to FIGS. 2A, 2B and 3, hot water heater 114 will be describedin more detail. The hot water heater 114 includes a tank 210 havingcylindrical side walls enclosed by a cover 212 and a base 213. Waterfrom hot water supply line 128 is supplied through water inlet 214provided near the base 213. Hot water exits the tank 210 through a hotwater outlet 216 located at cover 212. Located coaxially with and incommunication with outlet 216 is a dip tube 218. The dip tube extendsdownwardly from the interior of cover 212 within the tank. Water exitsthe interior of tank 210 through an opening at the end of dip tube 218so that the level of water in the tank should never rise significantlyabove the bottom end of the dip tube. This creates a head space or airballast 220 between the water surface and the cover 212 when the tank isfilled.

Two check valves are provided in or near cover 212. An atmospheric checkvalve 224 is provided in an extension or chimney 222 extending from thecover 212. Atmospheric check valve 224 acts as a pressure relief valveto set a maximum pressure in the tank and can be adjustable. This valveprotects the tank from overpressurization. Hot water outlet valve 130can be designed as a back-up for this function. A vacuum check valve 228is provided in flange or collar 226 also connected with the cover 212 atany elevation above the water level. Vacuum check valve 228 preventsnegative pressure from generating in the tank when, for example, asubstantial amount of cold water flows into the tank, which may causesteam in the head space to condense and otherwise cause a negativepressure. Vacuum check valve 228 allows air from outside of the tank topass into the head space to equalize the pressure when such negativepressure condition develops. Check valves 224 and 228 communicate withthe head space 220 defined by dip tube 218. This head space enables thetank to react to changes in temperature and pressure and maintaindesired pressure conditions.

Working together, valves 224 and 228 define a minimum (e.g.,atmospheric) and a maximum pressure in the tank. It has been found thatwhen the relief pressure of valve 224 is set relatively high (e.g., 5-7psig), use of vacuum check valve 228 is not necessary. However, if therelief pressure of valve 224 is relatively low (e.g., 34 psig), such avacuum relief valve may become necessary to prevent the development ofnegative pressure in the ballast that would otherwise be caused by therapid entry of cold water or by the heater's own power supply beingdisconnected. This is because at a relatively high pressure (5-7 psig),a vacuum is typically not created in the head space even when asubstantial amount of cold water flows into the tank, but such mayreadily occur when the relief pressure is set to a lower level (e.g., 34psig).

During the water heating process large amounts of dissolved air becomereleased from solution in the water and can be observed as bubblesrising upward in the tank and collecting in the head space at the top ofthe tank. A major benefit of relief valve 224, besides maintaining auniform water pressure in the tank, is to provide a means to remove or“eject” the excess air from solution. If this air were not removed, theair would exit in the flow of hot water from the heater into the mixchamber. If air bubbles enter into the mix chamber, the flow of hotwater through the mix chamber would not be uniform. Non-uniform flow ofhot water results in varying concentration of tea product in the mixchamber and can be viewed by the user as clear and dark volumes offinished tea product dispensed from the nozzle. The apparatus describedin U.S. patent Application Publication No. 2002-0074350 uses anelaborate air ejection mechanism to remove air and facilitate theuniform flow of hot water to the mix chamber. The present inventionprovides an improved method of removing air by combining the function ofwater heating and air ejection into a single water heater assembly asdescribed herein, which provides a uniform back pressure to the mixchamber and removal of all the air that becomes disassociated from thewater as the water is heated. The net result is a simplified andeconomical approach to provide uniform flow of hot water to the mixchamber that results in superior product homogeneity.

When the hot water control valves 112 and 130 are closed and the waterheating unit heats the water, the pressure in the head space may rise tothe maximum release pressure. When the hot water control valves areopen, hot water will be forced through the mix chamber at a higher thandesired flow rate due to the pressure in the head space. However, thispressure quickly dissipates and the hot water flow quickly reaches asteady state at a desired supply pressure of about 1 psig maintained inthe head space. The steady state pressure supply can give the appearanceof gravity-fed dispensing as in a conventional brewing urn.

Tank 210 is heated by a low watt density or low power density heaterblanket 230 which is fitted tight to the tank 210 and encapsulated by ashell 232. The shell can be in the form of two semi-cylindrical halvesthat can be bolted together at their edges to encapsulate the heaterblanket 230. The compression of heater blanket 230 by shell 232 improvesthermal transfer between the heater blanket and the water containedinside the tank. The low watt density of the blanket, typically lessthan 3 watts per square inch, reduces the temperature of the insidesurface of the tank as compared to conventional immersion heaters withmuch higher watt densities, e.g., greater than 100 watts per squareinch. The lower surface temperature improves heater efficiency andreduces the precipitation of mineral scale onto heat transfer surfacesthat can result in reduced operating life of the heater. Scale formationcreates a resistance to heat transfer and over time can increase heatertemperature to the point that the electric resistance elements in theheater blanket will fail.

A primary water temperature sensor 234 formed of an encapsulatedtemperature sensing element such as a thermocouple or thermistor isprovided in contact with the water in the tank 210 to measure itstemperature. A controller 400 will supply energy to heater blanket 230to heat the water in the tank until it reaches a predeterminedtemperature as measured by water temperature sensor 234. A tanktemperature sensor 236 such as a bi-metallic thermostat element isprovided in contact with the exterior surface of tank 210 to measure itstemperature. If the temperature of the exterior of the tank rises abovea predetermined level, the thermostat 236 is used to break the supply ofenergy (i.e., supply voltage) to the heater blanket 230 to preventoverheating. The thermostat is thus a redundant control to preventoverheating in the event of a failure of the primary temperature sensor234.

To further increase heating efficiency, tank 210 can be covered withinsulation 238. Insulation is provided around the side walls as well astop and base of the tank. A drain 240 is provided at the lowest point oftank 210 and is normally closed by an end stop 241. In the event of longperiods of non-use, the tank can be drained completely through drain240.

The tank 210 produces hot water within a predetermined range. The hotwater is preferably in the range of 140-200° F., more preferably in therange of 175-185° F., and most preferably is 180° F. A temperature thatis too high may cause the water to boil over. Additionally, during highvolume dispensing, the temperature may drop. While this lowertemperature produces a product of lesser quality, it is still sufficientto produce the mixed beverage. The hot water inlet flow control valve112 controls the flow rate of water into the tank 210. The incomingwater enters the tank 210 at a controlled flow rate and pushes heatedwater out of the tank at the same flow rate. A preferred volume of thetank is a relatively small, 0.75-1.5 liters, which facilitates rapidheating of the water. The low-pressure operation of the tank, withoutwide variation in pressure, contributes to a uniform flow of endproduct, causing the dispensed product to appear to be flowing from areservoir, such as from a real leaf tea brewing urn.

When the controller 400 supplies voltage to the heating blanket to heatthe water in the tank, both inlet and outlet hot water valves 112 and130 are normally closed as long as the system is in a non-dispensingmode. Outlet hot water valve 130 is necessary to isolate the tank duringthe heating cycle to contain the expansion of water in the tank as thewater is heated. If valve 130 did not exist or were opened during theheating cycle, hot water would expand and rise up the dip tube 218 andenter into the mix chamber. This overflow of hot water into the mixchamber would result in greatly diluted tea product during theinitiation of the normal dispensing function, and would be experiencedas clear hot water flowing from the nozzle. Generally, hot water valves112 and 130 will operate simultaneously during the normal productdispensing function to provide instantaneous and uniform hot water flowto the mix chamber.

Referring again to FIG. 1, in the mixing chamber 122, a concentrate ismixed with hot water and cold water. The concentrate can be suppliedthrough a fitment 135 and pumped by a gear pump 136. Gear pump 136 canbe DC-powered and can provide practically pulseless concentrate deliveryfor better homogeneity. The flow capacity of the concentrate can beadjusted by varying the DC voltage supply or via pulse width modulation,which modulates pump speed.

The beverage concentrate can be of any concentration ratio, with themixing ratios of concentrate, hot water, and cold water being adjustedaccording to the specific concentration ratio. In a preferredembodiment, the beverage concentrate is nominally a 100:1 dilution ratiobased on volume, allowing storage of the highly concentrated beveragewithin a relatively small space. The beverage concentrate can besupplied in a disposable plastic bag. Since the concentrate can becostly, it is beneficial to be able to fully evacuate the plastic bagwith little or no remnant, which requires proper support of the plasticbag within the system. One method is to support the plastic bag via aconventional “bag-in-box” approach. The preferred method is to hang theplastic bag from hooks (not shown) attached to a support structure (notshown) of the system, which results in a more complete evacuation of theconcentrate from the plastic bag.

In order to activate certain flavor components and to effectively mixand dissolve the concentrate, this extraction should be mixed with hotwater at a temperature in a range of around 175-185° F. At lowertemperatures, the mixture may not remain in solution. In the preferredembodiment, the concentrate is first mixed with hot water in the mixingchamber at a ratio of about 10:1 and the hot water/concentrate mixtureis then mixed with cold water at a ratio of about 9:1 further downstreamin the mixing chamber. Thus, the resulting beverage mixture will have aconstituent ratio of cold water, hot water and concentrate of about90:10:1.

A substance for adding aroma to the dispensed mixture can also besupplied to the mix chamber. This aroma substance can be providedthrough a fitment 160 and also pumped by a DC-powered gear pump 162. Thearoma substance is very concentrated and supplied or injected atextremely low dosage, for example, on the order of 8 grams per minute.Typical gear pumps normally do not operate at such a low discharge rate.Accordingly, a return line 164 is positioned to establish fluidcommunication between a discharge line 163 of pump 162 and fitment 160.A variable restriction 165 is provided in return line 164. By varyingrestriction 165, a precise amount of aroma substance can be returnedback to the source while allowing a fraction of the substance dischargedby the pump to enter the mix chamber. Alternatively, the flow rate ofaroma can be further restricted by placing an additional flowrestriction at the aroma inlet to the mix chamber. In addition, anotheradditive, such as a sweetener can be selectively supplied through aseparate line 144 to the mix chamber. The sweetener can be controlled bya solenoid valve 142.

Pressure switches can be used to monitor the supplies of theconcentrate, aroma substance, and sweetener to determine when thesupplies of these various components are depleted.

A more detailed description of the mix chamber 122 will be describedwith reference to FIGS. 4, 5A and 5B. The mix chamber includes acylindrical housing 310 with a central bore 311 and various supply ports312, 314, 316, 318 and 320, as well as a discharge exit 322. Hot wateris supplied through an axial inlet 312 that is provided coaxially withthe central bore 311 of housing 310. Downstream of axial hot water inlet312 is cold water inlet 314. Cold water inlet 314 is disposed at anangle transverse to the axis of the housing and preferably at an angleless than 90°. The cold water inlet port 314 is preferably angled in theflow direction, as shown in FIG. 4, to help maintain uniform flow. Aconcentrate inlet 316 is disposed between hot water inlet 312 and coldwater inlet 314. Inlet 320 is provided between concentrate inlet 316 andcold water inlet 314 and can supply the aroma substance. Inlet 318 isprovided downstream of the cold water inlet and can be used to supply anadditive such as sweetener. The additive port is preferably located onthe bottom of the mixing chamber 122. This positioning allows theadditive to stratify during periods of non-dispense. Stratification ispossible because the additive has a higher specific gravity than thebeverage product. For example, a liquid sweetener has a higher specificgravity than a tea product. It is also desirable to keep the sweetenerfully concentrated during periods of non-dispense to maintain theeffectiveness of sterilizing agents in the sweetener.

The assignments of the various constituents to particular inlets as wellas the positioning of the various inlets are not limited to thatdescribed above. However, it is preferred that hot water be supplied atthe inlet furthest upstream to enable hot water to rinse the entiremixing chamber in a rinse cycle. Further, it is preferred that theconcentrate inlet be disposed adjacent the hot water inlet to enable aresidence time of the concentrate with the hot water before the coldwater is introduced. This residence time can range from 0.1-2.0 seconds,for example, as desired. A residence time of about 0.5 is desired in oneapplication. That residence time can be controlled by adjusting the flowrate with respect to the distances between the hot water, concentrateand cold water inlets.

The mixing chamber 122 mixes the beverage solution, and it is preferablefor the mixing chamber to have a gradually reducing hydraulic diameterfrom its entrance to its exit. The gradually reducing hydraulic diameterprovides additional mixing of the beverage solution. Additionally, themixing chamber 122 may have internal flow vanes (not shown) on theinternal surface of, or inserted into, the mixing chamber to furtherdirect and mix the beverage solution.

At the exit of the mixing chamber 122, the beverage solution emptiesinto the nozzle assembly 151, where the flow direction is changed fromhorizontal to downward. The change in flow direction further enhancesmixing. A converging nozzle 152 is threaded onto the nozzle assembly151. Flow is directed through the nozzle 152 and into a cup or pitcherof the user. The nozzle 152 may have internal flow vanes (not shown) tohelp straighten the flow and minimize splashing. It is preferable forthe nozzle 152 to be threaded onto the nozzle assembly 151 such that thethreads are not exposed to the beverage product, making the systemeasier to clean.

The mixing chamber 122 of the present invention provides good mixing ofthe beverage product that produces a homogenous flow with no colorvariation due to incomplete mixing, and is drainable and cleanable withhot water to reduce the growth of bacteria. It is preferable to mold themixing chamber assembly, or its components, with an antibacterial agent(for example, Microban™) mixed with plastic resin to discourage thegrowth of bacteria on the internal and external surfaces.

With the exception of hot water inlet 312, it is preferred that a checkvalve be provided at or near each of the other supply inlets. Each checkvalve 314 a, 316 a, 318 a, 320 a can be in the form of a duck billvalve. Each valve can be encapsulated within each inlet or within a barbfitting 314 b, 316 b, 318 b, 320 b attached to each inlet. Mix chamber122 can be formed of plastic or stainless steel, for example, and thecheck valves or barb fittings can be sonically welded or glued to themix chamber body. The check valves can prevent the back flow of themixture into the various inlet lines. The exit 322 of the mix chamber122 can be directly connected to the nozzle assembly 151 or a flange oradapter 152 a for connection with the nozzle assembly. Alternatively,the mix chamber can be formed integrally with the nozzle assembly.

In operation, controller 400, which can comprise a microprocessor on acircuit board, activates the associated flow control valves and pumpsand starts the dispensing process. Additionally, transformers providepower to the system.

The programmable microprocessor (not shown) provides intelligent controlof the system. The microprocessor controls the dispensing function(i.e., valve operation, pump operation, temperature control, etc.),monitors system status such as water temperature, number of drinksdispensed, and out of product sensors (concentrate and additive), cancontrol a daily hot water flush, provides service diagnostics, andprovides the ability to remotely poll the electronic status.

Referring to FIG. 6, the nozzle assembly 151 includes a lever 172,nozzle 152, a microswitch (not shown), and a switch depressor (notshown). The user initiates the flow of beverage product by pulling onthe lever 172. The lever 172 is linked to a pull rod that activates themicroswitch with the switch depressor. The lever 172 returns to theresting position by a biasing device or spring. The microswitch can bemounted to the rear of the nozzle assembly and is hidden from the user.Closure of the microswitch creates an input to the controller that inturn activates the associated flow control valves and pumps, and startsthe dispensing process. Alternatively, the microswitch can directlyactivate the associated flow control valves and pumps, and start thedispensing process.

If the system is first being used or is being used for the first time ina while, or the tank has been drained for some reason, the system mustbe initialized. Lever 172 is depressed so as to actuate at least hotwater control valves 112,130. Water is fed through hot water inlet line128 into the bottom of tank 210 while evacuating air from water outlet216. This evacuated air is passed through hot water outlet line 131through the mix chamber 122 and out the nozzle 152. If cold watersolenoid valve 156 is opened, the evacuating air will be evident in thedischarging cold water. The water level rises in the tank until itreaches dip tube 218, at which time water begins to flow through outletline 131. A continuous, smooth flow of water through the nozzle willsignal the operator that tank 210 is filled. There is no need for a tanklevel sensor.

In operation, after the water tank has been filled and the water heated,upon lever 172 being operated, the microswitch is activated to controlthe various valves and pumps. More specifically, hot water controlvalves 112, 130 and cold water valve 156 are opened simultaneously toinstantaneously provide flows of hot and cold water to the mix chamber122. The flow rates of these two valves are in fixed proportion andcontrolled by pressure regulator 126. At the same time, pumps 136 and162 pump concentrate and an aroma substance into the mix chamber andsolenoid valve 142 selectively opens to allow another additive, such assweetener, to also enter the mix chamber. The various constituents aremixed in the mix chamber and dispensed through nozzle 152. When thelever 172 is returned to its resting position, the microswitch isopened, and the microprocessor closes the flow control valves and shutsdown the pumps. The operation described above instantaneously terminatesthe flow from the nozzle assembly 151 as soon as the lever 172 isreturned to the resting position. Also, the operation of valve and pumpactivation and de-activation may be timed to make adjustments that couldimprove the homogeneity of the dispensed tea product.

FIG. 6 shows a conceptual design of exterior cladding 170 that providesthe appearance of a real leaf tea brewing urn but which is actually apost-mix system according to the present invention. The exteriorcladding 170 is attached to unshown support structure that mounts theindividual internal elements.

The preferred use of the beverage dispensing system is to produce abrewed iced tea beverage product. The “fresh brewed” process involvesthe initial mixing of tea concentrate with hot water in order to “brew”the tea. Dispensing flow rates of 2.5 ounces (74 ml) per second providethe look of iced tea dispensing from a real leaf tea brewer. For 100:1concentrate, the system uses about 0.25 ounces (7.4 ml) per second ofhot water, about 2.25 ounces (66 ml) per second of cold water, and about0.03 ounces (0.8 ml) per second of concentrate. If an additive is alsoused, then the amount of cold water may be reduced accordingly.

With the present invention, tea concentrate and hot water are initiallymixed in the mixing chamber. The initially-mixed tea concentrate/hotwater solution is then further mixed downstream in the mixing chamberassembly with a metered quantity of an aroma substance and a meteredquantity of cold water to produce the finished tea beverage. The coldwater reduces the temperature of the final product to a temperature thatis similar in temperature to the iced tea product dispensed from leaftea brewers. Preferably, the temperature of the dispensed tea product iswithin the range of 60-100° F., and more preferably within the range of70-90° F. The dispensed tea product should be dispensed into a cupcontaining ice, to produce an iced tea beverage. A sweetened tea optionis also provided, where a liquid sweetener (the additive) is added tothe solution. The liquid sweetener may be added directly to the solutionin the mixing chamber or mixed with the cold water and then with thesolution.

The “fresh brewing” process results in a superior product in terms oftaste, clarity, convenience and economy. There is also a distinctadvantage with respect to controlling the unwanted growth of bacteria ascompared to conventional leaf tea brewers where bacteria are not easilycontrolled.

The end user is led to believe that the product is freshly brewed icedtea from a real leaf tea brewer. Maintenance and operational costs tothe end user are greatly reduced, the exterior appearance is modern andpleasant, and convenience is enhanced.

The individual components of the present invention described herein arenot limited to application in beverage dispensing systems. For example,the hot water heater is useful in any application of heating a liquid.

It is preferable to use the present invention with computer hardwarethat performs the processing and implementing functions. As will beappreciated by those skilled in the art, the systems, methods, andprocedures described herein can be embodied in or with a programmablecomputer, computer executable software, or digital circuitry. Thesoftware can be stored on computer readable media, for example, on afloppy disk, RAM, ROM, a hard disk, removable media, flash memory,memory sticks, optical media, magneto-optical media, CD-ROMs, etc. Thedigital circuitry can include integrated circuits, gate arrays, buildingblock logic, field programmable gate arrays (FPGA), etc.

Although specific embodiments of the present invention have beendescribed above in detail, it will be understood that this descriptionis merely for purposes of illustration. Various modifications of thedisclosed aspects of the preferred embodiments, in addition to thosedescribed above, may be made by those skilled in the art withoutdeparting from the spirit of the present invention defined in thefollowing claims, the scope of which is to be accorded the broadestinterpretation so as to encompass such modifications and equivalentstructures.

1. A water heating apparatus comprising: a tank having a top, a waterinlet and a water outlet, said outlet provided at the top of said tank;a heating unit for heating water in said tank; a dip tube extending fromsaid outlet into said tank to establish a headspace between the top ofsaid tank and the water level in said tank; and a pressure check valvecommunicating with the headspace to maintain the headspace of said tankat no more than a predetermined maximum pressure.
 2. The apparatusaccording to claim 1, wherein said heating unit comprises a low wattdensity heater blanket.
 3. The apparatus according to claim 1, furthercomprising a vacuum check valve communicating with the headspace.
 4. Theapparatus according to claim 1, further comprising a temperature sensorfor sensing the temperature of the water in the tank and controllingsaid heating unit.
 5. The apparatus according to claim 4, furthercomprising a second temperature sensor for sensing the temperature of anoutside surface of said tank to prevent overheating of said tank.
 6. Theapparatus of claim 1, having no level sensing device.
 7. The apparatusof claim 1, wherein the tank has a volume of about 0.75 to about 1.75liters and wherein the apparatus is contained within cladding having theappearance of a real leaf tea brewing urn.
 8. The apparatus of claim 1,wherein the pressure check valve opens at a pressure in the range ofabout 5 to about 7 psig.
 9. The apparatus of claim 3, wherein thepressure check valve opens at a pressure in the range of about 3 toabout 4 psig.
 10. The apparatus of claim 1 further comprising: an inletvalve connected to the water inlet and an outlet valve connected to thewater outlet and a controller adapted to close the inlet valve and theoutlet valve before or upon initiation of heating.
 11. The apparatus ofclaim 4 further comprising: an inlet valve connected to the water inletand an outlet valve connected to the water outlet and a controlleradapted to open the inlet valve and the outlet valve upon demand forheated water.
 12. A method of heating water comprising: introducingwater into a water heating apparatus comprising a tank having a top, awater inlet, a water outlet, and a dip tube extending from said outletinto said tank to establish a headspace between the top of said tank andthe water level in said tank said outlet provided at the top of saidtank; heating the water in the tank with a low watt density heaterblanket to a temperature in the range of about 140° F. to about 200° F.,releasing gas from the headspace when the headspace of said tank reachesa predetermined pressure.
 13. The method of heating water of claim 12,wherein the water heating apparatus further comprises an inlet valveconnected to the water inlet and an outlet valve connected to the wateroutlet, further comprising: opening the inlet valve and the outlet valveupon demand for heated water.
 14. A water heating apparatus comprising:a tank having a top, a water inlet and a water outlet, said outletprovided at the top of said tank; a heating unit for heating water insaid tank; an inlet valve connected to the water inlet; an outlet valveconnected to the water outlet; and a controller adapted to open theinlet valve and the outlet valve upon demand for heated water.
 15. Theapparatus of claim 14 further comprising: a dip tube extending from saidoutlet into said tank to establish a headspace between the top of saidtank and the water level in said tank; and a pressure check valvecommunicating with the headspace to maintain the headspace of said tankat no more than a predetermined maximum pressure.
 16. The apparatus ofclaim 15, wherein the pressure check valve opens at a pressure in therange of about 5 to about 7 psig.
 17. The apparatus according to claim15, further comprising a vacuum check valve communicating with theheadspace, wherein the pressure check valve opens at a pressure in therange of about 3 to about 4 psig.
 18. The apparatus according to claim14, wherein said heating unit comprises a low watt density heaterblanket.
 19. The apparatus according to claim 14, further comprising asecond temperature sensor for sensing the temperature of an outsidesurface of said tank to prevent overheating of said tank.
 20. Theapparatus of claim 14, wherein the tank has a volume of about 0.75 toabout 1.75 liters and wherein the apparatus is contained within claddinghaving the appearance of a real leaf tea brewing urn.